Hello, Here is the difference. 1. Don’t be shy - this relatea to the actual behavior of being a shy person. So for example when you go to a party with a friend and you don’t know anyone they may say to you “come on don’t be shy” which means that they are asking you not to behave like a shy person. This first one is the most commonly used expression. 2. Don’t feel shy - this one, although grammatically correct, is not used. You can say and English speakers will understand but it just doesn’t sound right. Literally translated it means that someone is asking you not to feel (in your mind, heart, thoughts) shy, rather than asking you not to behave in a shy manner. The difference is very small. The first one has to do with an action or behavior the second one has to do with feelings. However, i would stick to “don’t be shy”. Let me know if you have questions!

In America, we say "don't be shy". It is a common phrase.

to be shy is more common than to feel shy

In America, we say "don't be shy". It is a common phrase.